A conventional vehicle seat is shown in, for example, Japanese Laid-Open Patent Publication No. 2005-247104. In the seat, a seat cushion is attached to a floor via front and rear legs, so that the seat can be retained in a use condition. An upper end portion of each of the front and rear legs is rotatably connected to a cushion frame. Conversely, a lower end portion of each of the front and rear legs is removably connected to the floor. Further, each of the rear legs has a retracting link that is extended therefrom. A distal end of the retracting link is rotatably connected to a recessed portion formed in the floor via a pivot member.
In order to move the seat from the use condition to a retracted condition, first, a lever (or a strap) provided on a rear surface of a seat back is pulled, so that a reclining mechanism is unlocked. Thereafter, the seat back is rotated forwardly so as to be superimposed on the seat cushion, thereby changing the seat to a folded condition. Next, the lever is further pulled, so that connecting devices between the front and rear legs and the floor side are respectively unlocked. Thereafter, the folded seat is pivoted rearwardly by pivoting the retracting link about the pivot member, so as to be received in the recessed portion of the floor. Thus, the seat can be changed from the use condition to the retracted condition.
However, in order to retract the seat thus constructed, it is necessary to perform at least three operations, i.e., (1) rotating the seat back and superimposing the same on the seat cushion, thereby changing the seat to the folded condition, (2) pivoting the folded seat rearwardly by pivoting the retracting link, and (3) receiving the folded seat in the recessed portion of the floor. In addition, a large force is required in order to pull the lever so as to unlock the reclining mechanism.
Another vehicle seat is shown in Japanese Laid-Open Patent Publication No. 2003-54297. The seat includes a rotational mechanism that can move the seat between a use condition and a retracted condition. The rotational mechanism may include a support shaft, and first and second spiral springs attached to the support shaft. The first spiral spring is arranged and constructed such that a biasing force is generated when the seat is moved from the use condition to the retracted condition. To the contrary, the second spiral spring is arranged and constructed such that a biasing force is generated when the seat is moved from the retracted condition to the use condition. According to the seat thus constructed, when the seat is moved from the use condition to the retracted condition, the rotational motion can be assisted by the biasing force of the second spiral spring. To the contrary, when the seat is moved from the retracted condition to the use condition, the rotational motion can be assisted by the biasing force of the first spiral spring.
However, the rotational mechanism of the seat includes two spiral springs. This may lead to increased manufacturing cost and increased weight.